Expression of telomerase gene and apoptosis related genes in benign and malignant breast lesion

Objective:To analyse the expression of telomerase and apoptosis related protein,and explore the possible mechanism of breast cancer development.Methods:Immunohistochemistry method(SP)was used to detect the expression of hTERT,p53 and bcl-2 in the tissues of 48 cases of human breast cancer and 42 cases of benign lesions in breast.Results: The positive rates of expression of hTERT,p53 and bcl-2 in breast cancer were 87.50%,56.25%and 54.17%,respectively. Compared with the groups of adjacent noncancerous and benign lesions,there was a significant difference among three types of tissues(P<0.05).The positive rates of expression of p53 and bcl-2 in the group with positive expression of hTERT were 64.28%and 61.90%,respectively,and their difference was significant compared with the negative group(P<0.05). Conclusion:There is a correlation between the activation of telomerases and p53 gene mutation in the development of breast cancer,and they are perhaps relation to the down regulation of bcl-2.

Expression of tumor necrosis factor related apoptosis inducing ligand receptor in glioblastoma

BACKGROUND： Receptors for tumor necrosis factor related apoptosis inducing ligand （TRAIL） include death receptor 4, death receptor 5, decoy receptor 1, and decoy receptor 2. Activation of death receptor 4 and 5 selectively kills tumor cells. OBJECTIVE： To detect TRAIL receptor expression in glioblastoma by immunohistochemistry and RT-PCR, and to compare this expression to that in normal brain tissue. DESIGN： Observational analysis. SETTING： Department of Pathology, the First Affiliated Hospital of Zhengzhou University; Henan Tumor Pathology Key Laboratory. PARTICIPANTS： Twenty-five patients （17 males and 8 females） who received glioblastoma resection were selected from the Fifth Affiliated Hospital of Zhengzhou University, between September 2003 to June 2004. All glioblastoma samples were diagnosed pathologically. Twenty patients （12 males and 8 females） with craniocerebral injury who received normal brain tissue resection were selected in the same time period. There were no significant differences in sex and age between glioblastoma patients or between craniocerebral injury patients （P 〉 0.05）. All patients and appropriate relatives provided informed consent, and this study was approved by the local research ethics committee. METHODS： Polyclonal antibody against TRAIL receptors and an immunohistochemical kit （batch number： 200502） were purchased from Boster Company, Wuhan. Immunohistochemistry： Expression of death receptor 4, death receptor 5, decoy receptor l, and decoy receptor 2 were observed in both glioblastoma and normal brain tissue. The experiment was performed according to the kit instructions, and positive staining was brown-yellow. Assessment： There were no positive signals （-）; weakly positive signals, positive cells 〈 25% （＋）; weakly positive signals, positive cells 25%-50% （＋＋）; strongly positive signals, positive cells 50%-75% （＋＋＋）; strongly positive signals, positive cells 〉 75% （＋＋＋＋）. Evaluation： Expression levels of TRAIL receptors were estimated in both normal brain tissue and glioblastoma. Expression of decoy receptor 1 and decoy receptor 2 mRNA in glioblastoma were detected by reverse transcription polymerase chain reaction, and expression of decoy receptor in glioblastoma was estimated. MAIN OUTCOME MEASURES： Comparison of death receptor and decoy receptor protein expression between glioblastoma and normal brain tissue; decoy receptor mRNA expression in glioblastoma. RESULTS： Death receptor protein expression was strongly positive （＋＋＋） in glioblastoma, while it was weakly positive （＋, ＋＋） in normal brain tissue. Therefore, expression rate of death receptor protein in the glioblastoma was significantly higher than that in the normal brain tissue （.~ 2 = 18.48, 23.03, P 〈 0.01）. Decoy receptor protein expression in the glioblastoma was significantly lower than that in the normal brain tissue （ x2 = 6.65, 18.76, P 〈 0.01）. The level of decoy receptor mRNA expression in glioblastoma was significantly higher than those of protein expression （ x 2 = 9.82, 10.09, P〈 0.01）. CONCLUSION： High expression of death receptor and low expression of decoy receptor are frequently observed in glioblastoma, suggesting that TRAIL receptor genes show an anti-tumor and expressive response during the initiation and development of the tumor. There are significant differences in decoy receptor expression between normal brain tissue and glioblastoma, suggesting that the restricted expression of decoy receptor in glioblastoma is regulated at the post-transcriptional level.

COMBINATION OF γ-INTERFERON WITH TRAIL AND CISPLATIN OR ETOPOSIDE INDUCES APOPTOSIS IN HUMAN NEUROBLASTOMA CELL LINE SH-SY5Y

Objective To study the effect of γ-interferon （IFNγ）, tumor necrosis factor related apoptosis inducing ligand （TRAIL）, and cisplatin or etoposide induced apoptosis in human neuroblastoma cell line SH-SY5Y and its possible molecular mechanisms. Methods The expressions of Caspase 8 mRNA and protein were detected with RT-PCR and Western blot analysis. The effects of IFNγ, TRAIL, IFNγ ＋ TRAIL, IFNγ ＋ Caspase 8 inhibitor ＋ TRAIL, IFNγ ＋ cisplatin ＋ TRAIL, and IFNγ ＋ etoposide ＋ TRAIL on the growth and apoptosis of SH-SY5Y cells were detected with the methods of MTT and flow cytometry. The relative Caspase 8 activity was measured with colorimetric assay. Results Caspase 8 was undetectable in SH-SY5Y cells but an increased expression of Caspase 8 mRNA and protein was found after treatment with IFNγ. SH-SY5Y ceils themselves were not sensitive to TRAIL, but those expressing Caspase 8 after treatment with IFNγ were. The killing effect of TRAIL on SH-SY5Y cells expressing Caspase 8 was depressed by Caspase 8 inhibitor. Cisplatin and etoposide could enhance the sensitivity of TRAIL on SH-SY5Y cells. The relative Caspase 8 activity of SH-SY5Y cells in IFNγ ＋ TRAIL group was significantly higher than those of control group, IFNγ group, TRAIL group, and inhibitor group （ P 〈 0. 01 ）. There was no significant difference among IFNγ ＋ TRAIL group, IFNγ ＋ cisplatin ＋ TRAIL group, and IFNγ ＋ etoposide ＋ TRAIL group. Conclusions IFNγ could sensitize SH-SY5Y cells to TRAIL-induced apoptosis and this may be realized by the up-regulation of Caspase 8. Cisplatin and etoposide could enhance the killing effect of TRAIL on SH-SY5Y cells.

Apoptosis and Expression of Protein TRAIL in Granulosa Cells of Rats with Polycystic Ovarian Syndrome

The relationship between apoptosis of granulosa cells and follicle development arrest in polycystic ovarian syndrome (PCOS) rats, and the contribution of tumor necrosis factor related apoptosis inducing ligand (TRAIL) in apoptosis of granulosa cells were explored. By using sodium prasterone sulfate rat PCOS model was induced. The apoptosis of granulosa cells in ovaries of rats was observed by TdT-mediated dUTP-biotin nick end-labeling (TUNEL), and the expression of TRAIL protein and mRNA in granulosa cells was detected by using immunhistochemical staining and reverse transcription polymerase chain reaction (RT-PCR) respectively. The apoptotic rate and the expression of protein TRAIL in granulosa cells were significantly higher in antral follicles from the PCOS rats than in those from the control rats (P<0.01, P<0.05). There was no significant difference in apoptotic rate and the expression of TRAIL protein in granulosa cells of preantral follicles between the PCOS rats and the control rats (P>0.05). No apoptosis and the expression of TRAIL protein in granulosa cells of primordial follicles were found in the two groups. The expression of TRAIL mRNA was significantly stronger in granulosa cells from the PCOS rats than in those from the con- trol rats (P<0.01). It was suggested that the apoptotic rate in granulosa cells was significantly higher in antral follicle from the PCOS rats than in those from the control rats. TRAIL played a role in regu- lating the apoptosis of granulosa cells in PCOS rats.

Mkrn2 deficiency induces teratozoospermia and male infertility through p53/PERP-mediated apoptosis in testis

The apoptosis that occurs in the immature testis under physiological conditions is necessary for male germ cell development,whereas improper activation of apoptosis can impair spermatogenesis and cause defects in reproduction.We previously demonstrated that in mice,the makorin-2(Mkrn 2)gene is expressed exclusively in the testis and its deletion leads to male infertility.To understand the potential molecular mechanism,in this study,we found that levels of apoptosis in the testis were abnormally high in the absence of Mkrn 2.To identify specific gene(s)involved,we performed digital gene expression profiling(DGE)and pathway analysis via gene set enrichment analysis(GSEA)and the Kyoto Encyclopedia of Genes and Genomes(KEGG)database,and we found that MKRN2 inhibits p53 apoptosis effector related to PMP22(PERP)expression and that levels of the protein in sperm samples have an inverse correlation with infertility levels.GSEA additionally indicated that PERP is a negative regulator of spermatogenesis and that its ectopic expression induces male infertility.Further,Gene Expression Omnibus(GEO)dataset analysis showed that p53,upstream of PERP,was upregulated in oligoasthenoteratozoospermia(OAT).These observations suggest that Mkrn 2 is crucial for protecting germ cells from excessive apoptosis and implicate Mkrn 2-based suppression of the p53/PERP signaling pathway in spermatogenesis and male fertility.

Modulation of the DNA repair system and ATR-p53 mediated apoptosis is relevant for tributyltin-induced genotoxic effects in human hepatoma G2 cells

The toxic effects of tributyltin（TBT） have been extensively documented in several types of cells, but the molecular mechanisms related to the genotoxic effects of TBT have still not been fully elucidated. Our study showed that exposure of human hepatoma G2 cells to 1–4 μmol/L TBT for 3 hr caused severe DNA damage in a concentration-dependent manner. Moreover, the expression levels of key DNA damage sensor genes such as the replication factor C, proliferating cell nuclear antigen and poly（ADP-ribose）polymerase-1 were inhabited in a concentration-dependent manner. We further demonstrated that TBT induced cell apoptosis via the p53-mediated pathway, which was most likely activated by the ataxia telangiectasia mutated and rad-3 related（ATR）protein kinase. The results also showed that cytochrome c, caspase-3, caspase-8,caspase-9, and the B-cell lymphoma 2 were involved in this process. Taken together, we demonstrated for the first time that the inhibition of the DNA repair system might be more responsible for TBT-induced genotoxic effects in cells. Then the generated DNA damage induced by TBT initiated ATR-p53-mediated apoptosis.